Did you catch the juicy nugget of statistical jujitsu that AstraZeneca (AZN) and Nektar Therapeutics (NKTR) buried in Monday's press release announcing "positive" results from the two pivotal trials of its opioid constipation drug naloxegol? One of those naloxegol studies -- dubbed KODIAC-05 -- might have failed. Here's the key statement about the conduct of the KODIAC-05 study that AstraZeneca and Nektar sunk deep in Monday's announcement: After initial locking of the database for KODIAC-05, data associated with one patient that was previously assessed as non-retrievable was found to be retrievable. These data were added to the database and the database was again locked and underwent a final analysis. Once a clinical trial database is locked, it needs to stay locked. Locking and unlocking a database raises the risk that data can be improperly altered or manipulated. AstraZeneca insists proper procedures were followed and the naloxegol analysis presented Monday is accurate. But it's also plausible to believe AstraZeneca found no statistically significant difference in response rates between naloxegol at either the 12.5 mg or 25 mg dose compared to placebo. [AstraZeneca admits the 12.5 mg dose of naloxegol showed no benefit.]